1. Technical Field
The present invention relates to a semiconductor device and a semiconductor device manufacturing method.
2. Related Art
Conventional art is known for forming an aluminum electrode on a barrier metal layer, as an emitter electrode of an insulated gate bipolar transistor (referred to hereinafter as an IGBT), as shown in paragraph 0027 of Patent Document 1, for example. Furthermore, a technique is known for ameliorating crystal defects by injecting protons into a semiconductor substrate and then annealing the semiconductor substrate, as shown in Patent Document 2, for example. In addition, it is known that, by injecting protons into a semiconductor substrate and then annealing the semiconductor substrate, the vacancy (V), oxygen (O), and Hydrogen (H) form VOH defects and these VOH defects act as donors that supply electrons, as shown in Patent Document 2, for example.
Patent Document 1: Japanese Patent Application Publication No. 2006-080110
Patent Document 2: International Publication WO 2013/100155
A barrier metal used for an emitter electrode has an effect of shielding the semiconductor substrate from the protons being injected thereto. Therefore, even when protons are injected into the semiconductor substrate through the barrier metal and thermal processing is performed, a sufficient amount of defects are not repaired. Therefore, proposals have been made to repair the defects by, before the barrier metal is formed, injecting protons into the semiconductor substrate from the front surface side of the semiconductor substrate where the emitter electrode is provided and performing thermal processing, and then repairing defects by injecting protons into the semiconductor substrate from the back surface of the semiconductor substrate where the collector electrode is provided and performing thermal processing. However, when the number of thermal processes performed after proton injection increases, the manufacturing cost also increases.